Add task to create all indexes (#892)

* Add task to create all indexes

* Update changelog and readme

* Address review comments

* Control verbosity of the index creation

CHANGELOG.md

@@ -4,6 +4,8 @@
 
 ### New Features
 
+* [#888](https://github.com/toptal/chewy/pull/892): Rake task to create missing indexes ([@konalegi](https://github.com/konalegi))
+
 ### Changes
 
 ### Bugs Fixed

README.md

@@ -1197,6 +1197,10 @@ Right now the approach is that if some data had been updated, but index definiti
 
 Also, there is always full reset alternative with `rake chewy:reset`.
 
+#### `chewy:create_missing_indexes`
+
+This rake task creates newly defined indexes in ElasticSearch and skips existing ones. Useful for production-like environments.
+
 #### Parallelizing rake tasks
 
 Every task described above has its own parallel version. Every parallel rake task takes the number for processes for execution as the first argument and the rest of the arguments are exactly the same as for the non-parallel task version.

lib/chewy/rake_helper.rb

@@ -268,6 +268,24 @@ def delete_by_query_options_from_env(env)
           end
       end
 
+      def create_missing_indexes!(output: $stdout, env: ENV)
+        subscribed_task_stats(output) do
+          Chewy.eager_load!
+          all_indexes = Chewy::Index.descendants
+          all_indexes -= [Chewy::Stash::Journal] unless Chewy.configuration[:journal]
+          all_indexes.each do |index|
+            if index.exists?
+              output.puts "#{index.name} already exists, skipping" if env['VERBOSE']
+              next
+            end
+
+            index.create!
+
+            output.puts "#{index.name} index successfully created"
+          end
+        end
+      end
+
       def normalize_indexes(*identifiers)
         identifiers.flatten(1).map { |identifier| normalize_index(identifier) }
       end

lib/tasks/chewy.rake

@@ -57,6 +57,11 @@ namespace :chewy do
     Chewy::RakeHelper.update_mapping(name: args[:index_name])
   end
 
+  desc 'Creates missing indexes'
+  task create_missing_indexes: :environment do
+    Chewy::RakeHelper.create_missing_indexes!
+  end
+
   namespace :parallel do
     desc 'Parallel version of `rake chewy:reset`'
     task reset: :environment do |_task, args|

spec/chewy/rake_helper_spec.rb

@@ -470,6 +470,59 @@
     end
   end
 
+  describe '.create_missing_indexes!' do
+    before do
+      [CountriesIndex, Chewy::Stash::Specification].map(&:create!)
+
+      # To avoid flaky issues when previous specs were run
+      expect(Chewy::Index).to receive(:descendants).and_return(
+        [
+          UsersIndex,
+          CountriesIndex,
+          CitiesIndex,
+          Chewy::Stash::Specification,
+          Chewy::Stash::Journal
+        ]
+      )
+    end
+
+    specify do
+      output = StringIO.new
+      described_class.create_missing_indexes!(output: output)
+      expect(CitiesIndex.exists?).to be_truthy
+      expect(UsersIndex.exists?).to be_truthy
+      expect(Chewy::Stash::Journal.exists?).to be_falsey
+      expect(output.string).to match(Regexp.new(<<-OUTPUT, Regexp::MULTILINE))
+UsersIndex index successfully created
+CitiesIndex index successfully created
+Total: \\d+s\\Z
+      OUTPUT
+    end
+
+    context 'when verbose' do
+      specify do
+        output = StringIO.new
+        described_class.create_missing_indexes!(output: output, env: {'VERBOSE' => '1'})
+        expect(output.string).to match(Regexp.new(<<-OUTPUT, Regexp::MULTILINE))
+UsersIndex index successfully created
+CountriesIndex already exists, skipping
+CitiesIndex index successfully created
+Chewy::Stash::Specification already exists, skipping
+Total: \\d+s\\Z
+        OUTPUT
+      end
+    end
+
+    context 'when journaling is enabled' do
+      before { Chewy.config.settings[:journal] = true }
+      after { Chewy.config.settings.delete(:journal) }
+      specify do
+        described_class.create_missing_indexes!(output: StringIO.new)
+        expect(Chewy::Stash::Journal.exists?).to be_truthy
+      end
+    end
+  end
+
   describe '.journal_create' do
     specify do
       output = StringIO.new